How Does the \'override\' Keyword Ensure Correct Inheritance Behavior in C ?

Understanding the 'override' Keyword in C

In object-oriented programming, the 'override' keyword plays a crucial role in ensuring correct and intended inheritance behavior. It fulfills two primary purposes:

Clarity for Developers:

The 'override' keyword explicitly indicates that the method in a derived class is intended to override a virtual method declared in the base class. This provides clear guidance to other developers reading the code, signaling that the specific method redefines the behavior of the virtual method in the base class.

Type-Checking by the Compiler:

The compiler actively uses the 'override' keyword to perform thorough type checks. It ensures that the overridden method:

• Matches the exact signature (parameters, return type) of the virtual method in the base class.
• Adheres to the rules of covariant and contravariant returns based on the specified inheritance.

Consider the following example:

<code class="cpp">class Base
{
public:
    virtual int foo(float x) = 0; // Pure virtual method
};

class Derived : public Base
{
public:
    int foo(float x) override { ... } // Valid override
    int foo(int x) override { ... } // Error: Changes the signature
};</code>

In the above example, the 'override' keyword for the 'foo' method in the Derived class ensures that the inherited method matches the signature of the pure virtual method in the Base class. On the other hand, the attempt to override 'foo' with a different signature in the second method triggers a compiler error.

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